1. Field of Invention
The present invention relates to the technical field of auto parts, and more particularly to a multi-functional vehicle rearview mirror.
2. Description of Related Arts
A driver generally has the following requirements from a vehicle rearview mirror.
First of all, he or she wants to view each direction outside of the vehicle (i.e. the front, rear, left, and right sides of the vehicle) through an internal display of the rearview mirror, a freely and automatically shifting between a plurality of cameras is also desired. There are several problems difficult to be solved: one problem is the activation of the electric power of each camera and the cooperation between a video transmitting terminal and a video receiving terminal; another problem is that the wireless video transmitting module and the receiving module cannot maintain in the standby condition for a relatively long period of time, special vehicle lamp signal is also required for activating the video transmitting module and the receiving module of a predetermined direction. However, during an actual vehicle assembly process, the rear parts of the some of the vehicles are easy to be communicated to the signal of a reversing light while the front part of the vehicle is hard to have access to the signal of the reversing light. Therefore, a guide wire is provided to obtain the signal of the reversing light from the rear part of the vehicle for the display of the rearview mirror at the front part of the vehicle. The problem has been successfully solved by sending the signal of the reversing light to the rearview mirror at the front part of the vehicle by embedding with two RF transceiver modules.
A current rearview mirror of a car is embedded with a wireless video receiving module. If the wireless video receiving module is always kept in operation state, it is easy to be interfered by other proximal frequencies, so that the normal driving may be disturbed. Besides the wireless receiving module, the rearview mirror is further provided with a RF transceiver module which controls the electric power supply of the video receiving module. The rear part of the vehicle consists of three components which are a camera, a wireless video transmitting module, and a RF signal transceiver module. There are two methods for the electrical connection of the three components.
In one method, the three components are all electrically connected to the reversing light, so that the reversing light will be automatically supplied with electric power when shifting into a reverse gear. When electric power is transferred from the reversing light to three components, the video transmitting module will transmit the video information of the camera to outside, the RF module will send a signal to the RF receiving module within the rearview mirror of the vehicle so as to supply power to the video receiving module, so that the image information of the rear camera can be displayed on the display screen of the rearview mirror. A disadvantage of this method is that the driver has to shift into the reverse gear for viewing the situation at the rear side. Therefore, when the vehicle is running on a high way with a relatively high speed, the driver cannot view the situation at the rear side because the driver cannot shift the video image to the video image information provided by the camera at the rear side.
In another method, the ACC ignition wire and the reversing light are all electrically connected to a control system of the RF transceiver module at the rear part of the vehicle. When shifting into the reverse gear, the operation performance of the system is similar to the previous mentioned situation. When the vehicle cannot shifts into the reverse gear when running with a high speed and the driver does not want to shift into the reverse gear, if the driver wants to view the situation at the rear side of the vehicle, he can press on a RF transmitting controller near at hand, then a command can be received by the RF transceiver module adjacent to the camera, the RF transceiver module will send a signal to the RF receiving module of the rearview mirror so as to activate the video receiving and displaying system in the rearview mirror. At the same time, The RF transceiver module at the rear side of the vehicle switches on to supply power for the camera and the video transmitting module. Finally, the image information of the camera can be displayed on the display screen of the rearview mirror.
According to another aspect, during driving of the vehicle, the driver may also want to view information such as the information of the compass board, temperature information, incoming call information via Bluetooth, and the size of the display area should be as small as possible. That is because when this display area is used for displaying such information, it can be used for displaying view from the rear side of the vehicle. However, a relatively large area of the rearview mirror for displaying the view from the rear side of the vehicle is desired, so that a relative large view angel and vision can be increased so as to enhance the safety when driving. A special display device which is installed on the rearview mirror will add the cost of the product. Moreover, display screens with small size and high brightness are seldom manufactured by the manufacturer, so that the price may by even higher and the costs will be increased. The rearview mirror of a vehicle is often embedded with a display device with a size of 2.0 inches to 10.2 inches for viewing the video of the camera at the rear side of the vehicle or other DVD videos when the driver is backing the vehicle. The display device is not activated to operate when there is no backing operation of the vehicle. The working principle of the display device is described as follows: the activation board of the display device sends a display signal to the displaying liquid crystal glass, simultaneously other luminous beams are projected on the displaying liquid crystal glass, so that images can be viewed by eyes of the driver, so that the displaying function is provided. The projecting luminous beams on the displaying liquid crystal glass can be projected from the backlight module of the display device or from a backlight module of a small size. An window can be provided at the rear side of the display device in the rearview mirror for adding a backlight of a small size, when the backlight of the display device is closed and the displaying liquid crystal glass of the display device is activated, there will be graphics and text information shown on the export window, other areas is provided with black image. Simultaneously, the small sized backlight is projecting light beams which pass through the small window provided at the rear side of the display device in the rearview mirror and project on the displaying liquid crystal glass, so that an image displaying area of a relatively small size can be clearly viewed by the driver. Therefore, a displaying effect is provided on a very small sized screen on the rearview mirror of the vehicle during driving. Therefore, a display device not only can be used as a small sized displaying device when driving, but also can be used as the displaying device for cameras during backing of the vehicle or displaying DVD signals of DVD videos. Thus, the hardware is provided with two functions, the costs are reduced, but the size of the reflecting area of the rearview mirror is maximized.
Referring to FIG. 1, a conventional multi-functional rearview mirror includes a cover 1, a mirror 2 installed in the cover, a liquid crystal display device 3 which has a LCD 31 and a backlight (not shown in the drawings). LCD 31 is provided with a small sized display zone 311. In this type of multi-functional rearview mirror, the backlight of the liquid crystal display device is turned on when a full screen display effect is required for displaying the information from the camera during backing of the vehicle or displaying DVD videos. When some graphics and text information is required to be displayed on the small sized display zone on the rearview mirror when the vehicle is running forward. Since the small sized display zone 311 will not cover the whole screen, according to conventional art, other zones of the screen besides the small sized display zone 311 will be provided with backlight illumination. Even if the other zones are used for exporting back images, some luminous beams may be viewed from the other zones, so that it is not pleasing to eyes and the safe driving may not be guaranteed. The solution herein is that the backlight of the display device is turned off when the small sized zone is used to display information, and the added small sized backlight is turned on so that other zones of the display device is cut off from light source and will be completely dark, so that there will be no light beams which can pass glass and be viewed by the driver.